The overall objective of this Project is 1) to study monoamine oxidase (MAO) in various tissues of schizophrenic patients, their first degree relatives, other psychotic patients, and controls; 2) to study dopamine B-hydroxylase (DBH) activity in serum and brain of psychotic patients and controls; 3) to study various adenosine triphosphatase (ATPase) activities in red cells and other tissues of psychotic patients and controls; 4) to study serum prolactin levels as an index of dopaminergic activity in psychotic patients, as well as related serum prolactin studies in rats. This last objective is an interest which has developed from research conducted thus far, and is related to the dopamine hypothesis of schizophrenia, to which the Grant Proposal was partially devoted.